CLEF


Meaning of CLEF in English

clef /klef/ BrE AmE noun [countable]

[ Date: 1500-1600 ; Language: French ; Origin: 'key' , from Latin clavis ]

a sign at the beginning of a line of written music to show the ↑ pitch of the notes

treble/bass clef

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.